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When Geeks Build Green

The wildflowers planted in the meadow and now in a riot of bloom, and it seems like only half of the types have bloomed so far, so we have more colors to go. The grasses are slowly growing in in between. I understand from the sources I have read on Native California Grasses, that I should expect this first year to be mostly establishing root structure with a little bit of grass above the ground, and that next spring is when I can expect to see more growth. In the mean time, however, the flowers are giving us plenty of green.

Wildflower mounds in the back

The various edible cultivars of plants that we have in the yard are being grown in “guilds” of plants with an eye towards permaculture. Guilds are groups of plants that have been found to work very well together because they each provide something that the other plants around them need, whether it be acidification of soil, shade, nitrogen fixing or simply support for the other to grow on. If carefully selected and sited, guilds overall require less water, harbor fewer pests, suppress weeds, and are more more productive without needing chemical fertilizers. Our (grey water irrigated) fruit trees are interplanted with blueberry bushes. This year we are sheet mulching around the trees and bushes to bring the new trees through the hot summer with a minimum water requirement while they establish their roots. Sheet mulching consists of a layer of corrugated cardboard over the ground covered with compost and mulch to a foot deep and left to rot for a year, and it is excellent for suppressing weeds which otherwise would be a constant battle. Next spring after the sheet mulching has had a year to decompose, we will interplant legumes of various sorts all through the orchard. (You will also see that we have finally replaced our fence all the way around, getting rid of the rotting, leaning, broken eyesore that we had before and replacing it with a fence with a custom top lattice that echos the horizontal bar design theme within the house.)

The fruit tree orchard with blueberry bush interplantings, sheet mulch and the new fence visible along the right side

The citrus trees (two limes, one lemon) with feijoas, blackberry and raspberry. at the end of the path, the kiwi vines to be grown on the trellis can be seen.

Our citrus trees have pineapple guava (aka feijoa), blackberries and raspberries interplanted around them. We haven’t yet sheet mulched that area, so in the picture you can see that the weeds are already aggressive in that area.

As part of getting the fence replaced, we needed to move all of the piles and piles of stones that we had been hoarding all over the yard for the eventual construction of two ponds and a stream in the front and middle yards. We decided to assemble them into a dry creek bed of sorts running through the area where we will eventually have the stream so that we could plant all of the appropriate plants around that area before we built the stream (in one or two, or three years). It ended up looking surprisingly nice, and it is extremely useful for planning where plants are going to go. We’ve put in some douglas iris and various Juncus varieties that are difficult to grow from seed (I’ve been trying, and haven’t been too successful), and all around the stream bed on the greywater wetlands we’ve planted bull clover, so hopefully we’ll be seeing some of that coming up soon.

The dry creek running through the grey water wetlands

Other edible plants in the yard include an old fig tree that produces luscious pale green figs with bright red interiors, a couple of passiflora edulis varieties, huckleberries and currants and wild strawberries as part of the redwood understory in the front yard, and, of course, a kitchen garden of various different herbs including lots of mint for mojitos

Now that the house is in pretty good shape, it is time to start covering all of the bare earth around the house with plants. When we worked earlier with our landscape architect, Amy Cupples-Rubiano, she had put together a beautiful design with native plants and different climate zones in the yard. For the open, sunny, unirrigated areas the plan was for “open grasslands” – native grass and wildflower meadows that would go green in the winter rains, burst into color in the spring and then become a dormant golden brown during the summer. For the planters nearer the house on the sunny south side that tends to get very hot from both direct sun and reflection off a sunny wall, the plan was for chaparral species like manzanita. The shaded areas around the fruit trees would be filled with more shaded grassland species, the front yard would have redwood understory plants in around our huge Deodara tree in the front yard (and our new tiny redwood seedlings that we hope will grow up to join our neighbor’s redwood grove). The final “climate zones” are the greywater wetlands with rushes and bog plants that will live with their roots down in the greywater gravel leach field, and then the orchard which is watered from the output from the greywater wetlands.

It will be a multi year process getting all of these plants established, but I have started with a combination of broadcasting seeds in the meadows (seeds available from Larner Seeds, a specialty native plant seed company), starting the seeds that need more care in little greenhouse trays, and buying container plants from our local Summerwinds nursery that has a California Natives section, and, of course, the famous Yerba Buena nursery where huge numbers of native plants are available, and ordering bare root fruit trees. Where possible, I tried seeds, as container plants run $5-$15 per container, and I have a LOT of bare earth to cover.

Seedlings in the "jiffy" planter

There will be updates as I go along, but the following plant species are the ones going into the various parts of the garden:

The grey water system is now up and running! As was detailed in earlier posts, the house is double plumbed so that water from our bathroom sinks, showers and washing machine all flow out of our grey water sewer pipes for diversion into our grey water system, and the toilet sewage and kitchen sink water (aka “black water”) flows straight to the municipal sewer. Because our grey water exited a bit low to flow directly into our intended wetlands, we needed a sump pump to pump it back up to enter the grey water wetlands… except that those also needed to be constructed before we had anywhere for the water to go, so up until now, all the water (black and grey) has ended up in the municipal sewer.

A covered box needed to be constructed around the sump pump so the area could be buried but we would still have access to the sump pump for servicing, and the diverter valve should we ever need to bypass the wetlands and start dumping the grey water back into the main sewer (note the outflow pipe leading off in the direction of the wetlands)

During rough grading, our guys excavated a 15'x25'x2' deep "wetland" area in the middle yard which was to be filled with gravel for treatment of the grey water

Three trenches were then dug in the far back yard, lined with drain rock, and then perforated drain pipe. Check valves in line with the drains prevent siphoning of water back up into the wetlands. These pipes were then covered with a layer of drain rock, and reburied under the soil

The grey water pit was then lined with a protective liner to help keep the EPDM membrane (the water proof liner) from getting punctured. You can buy special material for this commercially, but we reused the spongey plastic separators that came in between the huge paving stones. Rather than throwing it away, it found a second use as our protective liner

An enormous (and astonishingly heavy) pond liner was then rolled out to fill the pit. We are using 40 mil EPDM which is available at specialty pond supply stores or by mail order on-line. It is more durable than the lighter weight PVC pond liner you can buy at Home Depot or Lowes

We partly filled the liner with water to help settle the bottom and smooth it out. Then landscape fabric "socks" were wrapped around perforated pipe which was plumbed to an overflow that passed through the EPDM membrane to flow into the now buried leach field. The pipe coming in from the left with an in-line check valve is the overflow from our rainwater cachement tank, so in a year of very heavy rainfall, our excess rainwater also gets dumped into the greywater leach field

This liner was then filled with (two and a half truck loads!) of 3/8" pea gravel, and Catherine discovered her little measurement error... the water would overflow the edge of the liner before flowing out of the pipe... the pass through, however, was a nice use of two toilet flanges that bolted face to face through the liner (with a 3" hole cut in it) making a water tight seal ... the guys at our local plumbing supply store know it is usually going to be something weird when Catherine walks in.

The pea gravel was then covered with landscape fabric and a little sand to keep it in place in anticipation of being buried... but things were on hold for yet another trip to the plumbing supply store in search of a solution for that pesky outflow issue...

A little plumbing ingenuity was all it took to bring the outflow pipe down to the right level, have an access point for draining the wetlands (should that ever be necessary), and still keep the grey water from flowing into the rainwater cachement tank...

Now when the water is filled up to the level of the top of the gravel, (but still a couple of inches below the liner top all around!) water starts to flow out of the outlet to the leach field. It is a beautiful thing. Grey water in one end of the wetlands, and cleaned water out the other end off to irrigate the yet-to-be-planted fruit trees

Then all that work is buried under a layer of mulch, and a bit of top soil with only the access drain peeking out.

We had talked about having a grey water wetlands construction party, but this construction ended up being dragged out over such a long time with such uncertain weather, that it really wasn’t practical to try to get a group together (and Catherine was stressed out and quite unpleasant to be around while sorting out the drainage issue). Our apologies to anyone who had their heart set on shoveling gravel, gluing pipe and schlepping liner. Should you want to do this yourself, feel free to contact us and come and see our system and see many many more detail photos.

Since “going live” about a week and a half ago, the wetlands have been handling all our grey water, and with the recent deluge, they have absorbed the rain with no problem at all, as it simply flows on out to the leach field. For those comparing this construction to the original plans, you will notice that the “soil islands” are missing. These are intended to increase the types of plants that can be planted with their roots down in the water to be treated. However, we will not be putting in the stream or the ponds for a while yet, and we decided that we would put in just a few plant types initially, and see how it fared through the winter. We wanted to make sure we didn’t have to do any significant rework of the basic wetlands before adding the other features, (and going to the effort and expense of putting in the stream). After all, there is still so much to do elsewhere in the house!